


Upon the Pleiades

by I_have_a_Mycroft_of_my_very_own



Series: Upon A Blackstar [2]
Category: Shadowhunters (TV)
Genre: Accidental Time Travel, Because I needed another WIP, I forgot Ragnor was green in the books, Time Magic, Time Travel, Wish Magic, maybe I should reread them
Language: English
Status: Completed
Published: 2019-06-07
Updated: 2019-06-15
Packaged: 2020-04-12 05:48:58
Rating: Not Rated
Warnings: No Archive Warnings Apply
Chapters: 5
Words: 9,179
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/19125850
Author URL: https://archiveofourown.org/users/I_have_a_Mycroft_of_my_very_own/pseuds/I_have_a_Mycroft_of_my_very_own
Summary: As a child, Magnus makes a wish and somehow it comes true... just not in the way he or anyone else was really expecting





	1. Grant a Child's Dream

**Author's Note:**

> So, this was originally just going to be added onto Memories (Of A Boy You Haven't Met Yet), but then my mind came up with another alternative. So, whenever I get around to writing it, which might be tomorrow or like a year from now... there will be another fic that follows actually deaged Magnus, and not 'actually, accidentally, a Time Traveller' Magnus. 
> 
> You DO have to read Memories (Of A Boy You Haven't Met Yet) before this one. 
> 
> Title is taken from The Seven Sisters by Celldweller. The story of Wish Upon A Blackstar (by Celldweller) is kind of the inspiration for this whole stupid thing... kind of.

“Alright, darling, while those two try and figure out what’s happened, I do have to ask. Were you doing any magic or anything before you arrived here?” Catarina asks, glancing at the adorable boy who will grow up to be her friend, and she’s certain that is what will happen, rather than discovering that Magnus has simply de-aged himself. The Time Magic surrounding the child is vibrant and she should know, it was what she dedicated a good portion of her studies to in the Spiral Labyrinth, after all.

“Hmm, I wished on the Sisters before I went to sleep and I woke up here.” The child replies, with a little frown.

“The Sisters?” Catarina questions, cocking her head to the side. Wish magic is especially powerful in young warlock children, but she’s never heard of anyone travelling through time as a result.

“The Sisters, the Stars of Stars.” The boy answers, his face scrunching up in annoyance when Cat doesn’t understand him. Cat hesitates, before conjuring a piece of paper and a pencil and handing them across to the boy.

“Can you draw them?” She queries and he considers the pencil and paper in front of him before nodding, quickly scribbling out a constellation that Catarina is _very_ familiar with.

“The Seven Sisters.” Cat replies with a nod, looking down at the drawing of the Pleiades. “What did you wish?”

“To be away!” Magnus says excitedly, before his face crumples, his shoulders slumping. “Somewhere safe… where I was-” he cuts himself off abruptly and shakes his head.

“-loved?” Cat asks, gently and the little boy nods at her, his eyes filling with tears that he quickly wipes away with a little sniffle that Cat knows he tries to hide. Unlike so many warlocks, Cat’s mother had loved her indefinitely and it’s something that has always broken her heart, to see so many of her own kind who never felt that. Magnus had told her, once, that his mother had loved him, truly, but that she could never reconcile the truth of him. “Well, I’m sure Ragnor, Alec, and I have enough love to go around.” Cat finally says, reaching out to ruffle the boy’s hair again, wonders if Alec had as much trouble as she is with making her mind not stutter over the fact that this boy, this child is _Magnus,_ or will become him, in time.

* * *

Ragnor pokes and prods at everything in the apothecary, but he already knows that nothing in here caused whatever is happening with Magnus. Knows it from the feel of the magic in the air, it’s Time Magic, capital letters, similar, but oh, so very different to Age Magic. Time Magic is a nightmare, absolutely and completely and Ragnor is not at all liking the fact that it appears their Magnus had absolutely nothing to do with causing it. No, if he’s reading the feel of the magic correctly, then he’s pretty sure the little boy sitting out at the table is the cause.

“What?” Alec asks him, impatiently. “You're making all sorts of faces right now, Ragnor. Normally when Magnus does that, he’s got something he doesn’t want to tell me.”

“Right.” Ragnor mutters, sighing and shaking his head. “Good news, the child _is_ Magnus. Bad news, he’s not _our_ Magnus, not yet, and won’t be for another eight hundred odd years. Well, he’ll become _my_ Magnus long before then, and Catarina’s shortly after that, but _your_ Magnus? No, he’s eight hundred years away.”

“In… English, please. The translation rune doesn’t work miracles, you know?” Alec requests, his voice so faint Ragnor is certain the Shadowhunter has actually already figured out what Ragnor is saying but can’t accept it.

“Time travel! Little Magnus has changed places with Big Manus.” Ragnor explains, before he starts laughing. “I wonder how happy the daft bastard is right now.”

“Probably not so much.” Alec answers, but he’s looking a little green. “He has to come back, though, right? They have to swap back because… otherwise he’ll never get _here_?”

“Exactly so, however, I’m pretty sure the little one caused this and I think he’s going to be the only one who can fix it and I’m not sure he’ll want to.” Ragnor says, looking out of the apothecary once more towards the child excitedly talking to Cat about one thing or another.

“He has to! Leaving aside the fact that I want my husband back, if he stays here, what the hell happens to our timeline?” Alec demands, but Ragnor just shrugs.

“Time is the ficklest thing in this world, Alec. If he stays, he erases his future, our past, but time will heal it, jumping through oh so many bloody hoops to set things right, the magic of it always makes an absolute mess, but Time ensures that Time continues, no matter what. But the child has to go back and we will ensure he goes back.” Ragnor promises, before leaving the apothecary and going to sit down across from Cat at the table.

“Time travel.” He posits to her, in English, knows the little boy between them won’t understand a word.

“Time travel.” Cat confirms, nodding her head. “He wished upon the Pleiades that he would be somewhere ‘away’ where he would be safe and loved.” Cat tells him, her voice full of the same sadness that his heart is. Magnus has always been the Sentimental one of their little trio.

Cat had her heart broken _once,_ she stitched it back together with stubbornness and determination, then she coated her heart in armour so strong it took he and Magnus more than a century to hammer through it. He’s let his heart be broken various times through the years, always a decision made after long, careful planning, never something done simply on spur of the moment. He can be reckless, but to be so reckless with your heart is… simply foolish. Armoured Catarina and Calculating Ragnor and Soft, Sensitive Magnus.

That’s not to say Magnus isn’t formidable when challenged, oh, no, no, he _earned_ his last name, his chosen name. Earned it through blood, sweat, and tears. Earned it through the screams of his enemies as their bodies hit the floor or floated away as dust on the wind. Magnus Bane learnt to fight at the knee of his father, but if there was one thing Asmodeus tried his absolute hardest to stamp out and _failed,_ it was Magnus’ capacity to love and his desire to be loved in return.

This child, who will tear entire cities down to their very foundations in the years to come. This child, who will discover portals in a few years, through trial and error on the battlefields of his father’s making. This child, who will live up to the very name he carries, the name his father chose and the one he did; _Great Death_ or _Powerhouse of Destruction._ This child, who first came to him broken, destroyed in body, spirit, and in mind. This child, who looks at him with wide, innocent, golden eyes, has a long dark path before him, and Ragnor must ensure he walks it.

“Do you have a warlock mark?” the child asks in flawless Indonesian, and Ragnor can’t help the laugh that pulls from his lips, as the question pulls him from his morose thoughts.

“Cat!” he exclaims to her, but she just grins and shrugs her shoulders.

“We’re the first of our kind the kid’s met, Ragnor. He’s curious.” Cat argues, rolling her eyes.

“Well, little one, it’s very rude to ask about one’s Warlock Mark, but because you asked so nicely, I’ll oblige just this once.” Ragnor tells the little troublemaker in the same language, letting his glamour bleed away, and smirking when he gets a jump out of Alec.

“Green.” Alec says, huffing. “All those stupid fucking vegetable endearments make so much more sense now!” the Shadowhunter mutters, rubbing at his face. Ragnor laughs and rolls his eyes.

“Of course.” He says, looking down at his hands when he finds Magnus inspecting them, Ragnor raises an eyebrow at him and then looks at Cat who shrugs.

“He probably wants to know what colour your magic is.”

“Oh.” Ragnor exclaims, before letting a harmless ball of purple fire form in his palm, grinning when Magnus’ eyes go wide and he lets out a little gasp, running his hands through the flame. “We’re really the first ones he’s met?”

“Mhm.”

“I’m not his first Shadowhunter, though.” Alec puts in, finally coming to sit at the table, opposite Magnus. “He freaked out when I drew my translation rune. Which I’ll have to draw again, soon.”

“I’m not surprised. Your lot used to be everywhere back then, you used to blink and find yourself face to face with one arsehole or another.” Ragnor tells him, with a roll of his eyes, very thankful for that to no longer be the case.

“Yeah, well it pisses me off.”

“Before you met him and fell all over yourself at him, what would you have done when you encountered him?” Ragnor questions, nudging his head towards the child and wrinkling his nose at the idea of playing devil’s advocate for arsehole Shadowhunters.

“He’s a kid!”

“Who has already murdered one mundane, oh, self-defence, of course! But he’s a warlock and a mundane died, the Clave makes no allowances for that, do they?” Ragnor questions, with a bitter smile on his face, the taste on his tongue when the Shadowhunter looks away.

“It’s not like that anymore. I made- I _make_ sure of it.” Alec says, his jaw clenched, Ragnor opens his mouth to reply but Cat speaks over him.

“They’re being very rude, aren’t they, dearest? Having a conversation that you can’t understand.” Catarina says in Indonesian, once more looking at the child.

“Adults do that all the time.” The boy replies, shrugging his shoulders, before he hesitates, like he wants to say something but isn’t sure how it’ll be received. Ragnor sighs at his own idiocy and gives Cat a look, that she returns with equal measure.

“Food.” They say together, before Cat goes to inspect the loft kitchen, to see if there is actually food in this house or if Magnus is still cheating.

* * *

Magnus frowns up at the stars above him with confusion, which only grows even more when the cold air whips against his skin, informing him that he is, in fact, naked as the day he was born. He huffs and conjures up clothing for him and pushes himself to sit up. Looking around him and then turns his attention back up to the stars, stars he hasn’t seen this clearly in… centuries. He purses his lips, closes his eyes and cocks his head to the side for a moment. Before he breathes in deep, licks his lips and casts a very detailed weather charm, that also happens to let him know the exact time and date.

He feels the parchment gently appear in the palm of his hand and he sucks in another breath, building up the courage to open his eyes, because something is _wrong_ and he doesn’t want to know. He _doesn’t_. He just wants to open his eyes and be back in his loft, waiting for his Alexander.

He opens his eyes.

**_“Fuck.”_ **

_Oh, and apparently, it’ll rain later. Wonderful!_

**Notes for the Chapter:**

> Unfortunately I don't think there'll be much of adult Magnus, unless I have him flitting around just having fun, because honestly, despite LOVING history and Classical Studies, my actual knowledge of history is like... bleh.


	2. It Makes No Difference Who We Are

**Notes for the Chapter:**

> Title from It Makes No Difference Who We Are by Celldweller
> 
> I'm still figuring out how I want to handle the whole 'hey, so little Magnus, we need you to go home so we can get our friend back' conversation...

Alec watches the boy, who will become his husband in eight hundred years, pick and prod at the food on the plate in front of him. _His_ Magnus still cheats as far as food is concerned. He'd explained once to Alec that there are special restaurants set up all over the world where warlocks can just order what they want and its magically available for transport at a moment’s notice. Magnus tried to explain the various different magical arts that went into making such a service possible, but it had all flown straight over Alec’s head. Cat had cheated, too, when she’d realized the only food in the loft is leftovers and felt she couldn’t really justify giving leftovers to a child who has no idea what modern food even _is._

So, the table is covered in as many different types of food from as many different parts of the world as Cat could reasonably get and some of it even Alec has never heard of, tried, or even seen before, so he doesn’t blame the kid for being suspicious of it. Ragnor’s enthusiasm for trying all the new or unknown dishes is actually a help, since the kid watches what Ragnor eats, and likes, then gives that a try, too. Alec watches quietly as Magnus turns his nose up at various dishes, all of which adult Magnus hates, too.

“What happens to my Mag… my husband if he doesn’t go back?” Alec finally asks, turning his attention back to the adult warlocks, who are each watching the little one with as much fascination as he had.

“He ceases to exist. Our memories warp, replacing him with some other warlock, or warlocks, who claim all his achievements, so that Time can progress, uninterrupted. Time protects itself.” Cat replies, monotone. “We remember, occasionally, that someone else actually did those things, but… it’s fleeting.”

“What does that mean for _me_?”

“The same. Your marriage, his title, they’re _his_ accomplishments. Whoever replaces him, takes over his life, Alec. He won’t be your husband anymore, that other warlock will." Cat explains, looking away from the kid, to stare up at the ceiling. “Time is eternal and self-healing. If we send Magnus back early enough, there won’t be any changes. If we don’t… things will start to warp around us, and we may not even notice. They'll undo themselves when he finally goes back, but if he never goes back...”

“So, we have to tell him, we have to explain to him. I’m not… if Magnus is never coming back then I’m not just going to forget him. I’ll kill myself first.” Alec promises, his lips pressing into a firm line. “I’m not going to live my life with some imposter replacing him. I won’t do it. That’s… such a betrayal.”

“You won’t have a choice, eventually you won't even remember there is anything wrong, but it doesn’t matter. We’re going to convince the little one to go home and when he does, we’ll get our Magnus back.” Ragnor states, rolling his eyes. “You’re both overthinking this. We tell the little one what’s happening, what we need. When he goes home Time will clear his memories, so he won’t have information he shouldn’t and things will continue on. The hardest part of all this is convincing him to go home. Once we accomplish that, he takes care of the rest.”

“Seriously?” Alec demands, raising an eyebrow. “How? Why can’t you just send him back?”

“Because he came here through wish magic and that’s the only way he’s going to return. None of us are powerful enough to return him, and wish magic becomes almost meaningless to warlocks when we reach our majority.” Cat explains, rubbing at her face.

“So, why can’t Madzie wish him back?”

“Madzie won’t do it. Madzie has decided that all children deserve to have a happy home, so if we tell her that for the ‘greater good’ we have to send Magnus back to an unhappy place, as he is literally orphaned and homeless at this age, she won’t go for it. I’m not going to lie to my daughter, either, so…” Cat says, shrugging her shoulders.

“Well, I mean… she’s right.” Alec admits with a sigh. “It’s ridiculous that in order to save my husband, I condemn my husband to centuries of what will become his worst nightmares.” Then he starts laughing, a broken little sound as a realization all but punches him straight in the face. “ _Break his heart to save his life._ That was the stupid deal I made with Asmodeus and look at us now!” he chokes, leaning forward to press his face into the table, wrapping his arms around his head as he breathes in ragged breath after ragged breath.

He knows that time was not kind to his husband, that from the time his mother killed herself and he killed his stepfather that his life became an escalating tale of bad deeds he committed or that were committed against him. Even now, they keep finding enemies his husband didn’t even know he had. Even now, they keep running headfirst into danger, into problems of their own making. When his husband would tell him stories from his childhood, all Alec had wanted was to bundle that kid up in his arms and tell him it would get better. Now he has that chance, all he wants is the kid to go back, so he can wrap the adult in his arms and never let them go.

“I’ll be back.” Alec says, sitting up and pushing away from the table and all but fleeing the loft before any of the warlocks can even speak. Stumbling on unsteady legs through the streets of Alicante, no destination in mind other than _‘away, away, away’_. Alec’s never been a coward, well, no, that’s not true. He has his moments, but he’s never stuck with them, always finds his courage somewhere along the way, to go back and face whatever he truly doesn’t want to. But this might be his limit. To save his husband, he has to doom his husband. He tried it the last time and it almost destroyed _him;_ he can’t do that again, yet if he doesn’t, he loses his husband forever. Loses him and won't even know it, won't even remember it. Has someone replace Magnus, totally and completely. Just… some stranger, slipping into his life, into the space Magnus had once occupied and he won’t even know it.

Stuck between a rock and a hard place, and by the angel, that phrase has never been so accurate.

* * *

Magnus stomps through one of the various forests of his home country, all the while swearing up at the stars above him, that he can no longer really see through the canopy, having realized exactly what’s happening.

“I said I wanted to be away! I didn’t say take me into the future!” Magnus all but screams at the twinkling stars above him, at one star cluster in particular. “How can you possibly be telling me that no one in this time could have loved me? That no one could have kept me safe?”

He has to have come back though, young him, he has to have, otherwise he wouldn’t have grown up… he wouldn’t have… but even if his younger self stays in the future, Time will fix it. He’ll never have existed. Everything he did in life since that wish will be… someone else’s accomplishments, someone else’s life. His marriage, his dreams with Alexander will be someone else’s.

 _“Fuck you!”_ he screams, falling to his knees and smashing his fists against the ground in front of him. His entire future rests in the hands of his past self. He wouldn’t give up Alexander, not for anything, if his past self is just as stubborn, just as selfish, he’s doomed.

* * *

When Alec gets back to the loft, it’s dark, but the rooms he’s come to associate with Catarina and Ragnor have added themselves to the loft and Alec wonders if they’re responsible for that, or if the inherent magic of the loft conjured them. He sighs at the empty living room and goes to the master bedroom and has to take a deep breath in when he sees the empty bed, but he finds courage somewhere, shuts the door behind him, and gets dressed for sleep. As if he truly believes he’ll be sleeping when his husband is not there beside him. But he lies down in bed all the same and hopes and prays.

* * *

Somehow, he must find sleep in the night, because he finds himself waking in the morning to the sun shining through the window. As always happens when Magnus is absent, he wakes up on Magnus’ side of the bed. Has to breathe through the intense wave of sadness, anger, and despair that suddenly rises up within him. He will get his husband back. He will, somehow, someway, he will get him back, he has to.

**Notes for the Chapter:**

> I haven't covered here because I couldn't figured out how to include it. Time, Creation (God), Destruction, Death, Life, Chaos, Order, etc are all siblings. Chaos and Order ensure the other's existence, without Order there cannot be Chaos, without Chaos there cannot be Order. Without Life there cannot be Death and vice versa. Without Creation, there cannot be destruction, etc, etc. But of them all Time is the only one that has no counterpart. Time IS and ALWAYS IS, so Time ensures that Time will always continue. 
> 
> In this situation, if young Magnus stays in the future, adult Magnus ceases to exist, and all his achievement disappear as well, but then the world Alec and them live in is suddenly impossible, which Time will not abide. So, instead, Time warps history, gives Magnus' achievements to another Warlock/Warlocks to ensure that portals still get created, to ensure that someone still picks Raphael up off the streets, to ensure that someone still crashes Alec's wedding, to ensure that someone seals the rift to Edom, etc, etc. No one who knew adult Magnus will remember him, if they do, it'll be flashes of memory that they do not linger on and quickly forget. If they send young Magnus back, Time undoes everything it did to protect itself, and that other warlock/warlocks are forgotten.


	3. A Dream Still Worth Saving

**Notes for the Chapter:**

> The angels tried and essentially FAILED to take Clary's memories and her runes, this will be explained later in the fic, probably. The fic is set after the show, but Clary never fully lost her memories or her runes and never went back to art school. 
> 
> Title from The Seven Sisters by Celldweller

After a long shower and throwing on whatever clothing first hit his fingers, Alec calls Jia, lets her know something has happened to Magnus and he won’t be available for work for he doesn’t know how long. Then goes out to the living room, he finds the kid sat on the couch, playing with wooden toys that Alec isn’t really sure where they came from, but he stands in the doorway and leans against the wall, watching the kid play. For a minute, he lets his brain convince him that this is Magnus’ kid, not Magnus himself, before reality sets in once more, and he coughs as he heads into the kitchen, letting the kid know he’s there.

The kid jumps, looking up at him with wide eyes, but neither of them speaks, until Alec draws the translation rune on wrist and grins at the kid.

“You hungry?” he asks, the kid nods enthusiastically and puts his toys down to go and sit at the table, looking at Alec expectantly. “What do you want? We’ve still got some food from last night.”

“Chow mein?” the kid demands, and Alec laughs and rolls his eyes. _His_ Magnus adored Chinese food, chow mein in particular, but then, _his_ Magnus wasn’t really all that picky, if he was hungry, he’d eat whatever was put in front of him, he wouldn’t be _happy_ about it, but he’d eat it. If he wasn’t hungry, he’d just ignore whatever the food was, until Alec had eaten it, or cleared it away.

He hums as he turns to the fridge and digs around the leftovers until he finds the chow mein, throwing it into a metal bowl, complete with lid, and scrawling the heat rune over the lid, before turning to find the fried rice for himself, and following the same tactic. When the food is hot enough, he swipes the stele through the heat runes and waits for them to fade away, before pouring the food out into two bowls and sticking forks in each, carrying them across to the table.

The kid’s eyes light up when Alec slides the bowl of chow mein in front of him and he excitedly starts digging in. Alec just sits across from him, watching the kid eat, while he picks absently at his fried rice and tries not to begrudge himself this moment. Even if Magnus will not ever remember this moment, he still deserves to have it, and Alec will find a way to convince the kid to go home, so he doesn’t have to feel bad about enjoying this.

“You’re sad.” Alec jumps a little at the unexpected statement and looks up from his food to frown at the kid.

“Why do you think that?” he asks, raising an eyebrow, regretting the question immediately when the kid seems to sink into himself, pushing his bowl away. “Hey, what’s wrong?”

“My mama was always sad.” The kid finally answers and Alec sucks in a breath and just barely resists smacking himself in the face, because of course. Magnus’ mother killed herself, but Magnus said she’d withdrawn from him slowly after she figured out what his eyes meant. Magnus had only been young… was only young, but he’d have seen how his mother was, even if he hadn’t fully understood all of what it meant.

“I am sad.” Alec admits, after a few moments of silence. “I’m missing my husband.”

“Where he go?” the kid, and honestly Alec is going to have to call him something else soon, queries, golden eyes watching him intently. Alec considers the question, debates the pros and cons of lying to the kid before finally thinking better of it. After their wedding, they’d made a promise that they would do their best not to lie to each other, even if little Magnus wasn’t involved in that, he’s _still_ Magnus.

“When you made your wish on the Sisters, you came here and he went wherever you came from. I don’t know if he’s coming back.” Alec answers, looking back down into his cooling bowl of fried rice, moving it around with his fork.

“Why?”

“Because… because you grow up to be him.” Alec says, letting the fork rest buried in the rice and pulling his phone from his pocket, he scrawls the translation rune on the back, before finding a video to show the kid, whose eyes have narrowed in suspicion.

_“Hey, Alec, I told you’d we’d keep ourselves entertained.” Clary says, grinning widely at the camera, before she moves and suddenly adult Magnus and Simon are there, covered in paint and laughing as they flick paint at each other with their paint brushes, their attempts at art abandoned on the easels behind them._

_“That’s cheating!! You cheating cheater who cheats!” Simon exclaims, as the paint suddenly swirls up around them and smashes against the vampire as Magnus’ hands glow blue, his eyes flickering before the glamour falls. “Clary!! Clary you have to save me! Uck, Magnus! That tastes disgusting! Wait, I’m not going to die, am I? Isn't paint toxic?" Simon yells, as paint gets in his mouth, Magnus laughs, clutching at his stomach as he tries to breathe._

_“Simon! You’re a vampire!” Clary tells him, exasperated as she ensures she’s out of their line of fire. “Just so you know, you’re paying for replacement paint, because… it doesn’t come cheap, yah know?”_

_Don’t worry, Biscuit, I’ll take care of it afterwards.” Magnus assures, the paint splattered across his clothing disappearing with a flick of his wrist and landing on Simon with a loud **SPLAT.**_

_“Isn’t the purpose of this whole thing to be getting to know each other better?” Simon whines, patting the paint absolutely soaking his clothes._

_“We are! We’ve all just learned that Magnus is a cheating cheater who cheats!”_

_“There wasn’t a rule about using magic!” Magnus argues, pouting and petulantly crossing his arms over his chest. “I was simply using my magic to my advantage. Simon has vampire super-speed; he could have totally moved out of the way.”_

_“Well, he’s not wrong.” Clary points out to the vampire who gasps at her in mock offense._

_“I see how it is, Fray! Abandon me at the first chance of mag- uck, MAGNUS!” the vampire shrieks, as he’s suddenly covered in glitter._

_“Ooops, my hand slipped.” Magnus says, innocently as Clary bursts into giggles and the video ends._

Alec watches the kid carefully, where he never took his eyes of adult Magnus for a single second. Alec quietly leans over to find a different video, letting it play.

_Magnus appears curled up on the couch, across from him Madzie’s tucked up in one of the armchair’s, Max on the other, all three fast asleep, all three dressed up in ridiculous costumes. Scattered around them looks like an explosion of candy, with Catarina standing in the middle of it glaring at the sleeping Magnus with her arms cross over her chest, while Alec can be heard quietly giggling behind the camera._

_“I told you he’d spoil them if you let him take her trick-or-treating.” Alec points out, still behind the camera, Cat sighs and rolls her eyes, marching over to stand beside him._

_“At least he got stuck with baby sitting duty, I guess.” She acknowledges, before gently using her magic to tidy up the candy. “If it was Ragnor, he’d have dropped them both home before the sugar rush ran out.”_

_“Yeah, that sounds about right.” Alec agrees with a little hum. “Magnus, at least, is a little bit more responsible than that, huh?”_

_“Hmm. Debatable.”_

Alec shows the kid how to use the phone, then leaves him to it as he tidies up the breakfast neither of them are going to continue eating. Alec leans on the kitchen counter and watches the kid, golden eyes never leaving the screen in front of him, rooted to the spot. Quietly, Cat comes to stand beside him, her eyebrow raised. Alec shrugs his shoulders back at her and turns his attention back to the kid.

If he was just a normal kid, or normal in their neck of the woods, and not actually the boy that would one day grow up to be his husband, Alec’s pretty sure he’d adopt him. Would have every excuse under the sun to justify randomly adopting a child to Magnus, but he can’t do that when the child _is_ Magnus. When keeping the child is the thing that ensures his husband might never come back.

Cat quietly lets Alec know that she’s going to see how Madzie is, before the warlock portals away. Alec stares at the portal as it disappears, before he goes to sit down at the table opposite the kid, who slowly looks up at him, his golden eyes more than just a little confused.

“He’s me?” the little kid asks, and Alec decides he’s calling him Magni, after the Norse God, so he can stop thinking of the kid, as ‘the kid’. If the name is good enough for a Norse God, it's good enough for the son of a Greater Demon/Fallen Angel.

“You grow up to be him, yeah. See, if you stay here, that never happens. He won’t have existed anymore.” Alec explains, taking a deep breath in and rubbing at his face, at the tears he can feel forming. “I know you don’t want to go back, if there was any way to have you both here, I’d do it in a heartbeat, but there isn’t.”

“I don’t want to go back. I want to stay here.” Magni replies, looking back down at the phone again.

“I know you do, but you can’t stay here. You have a future ahead of you, you do so many good things, you help save the world so many times. You make the world a better place, Magnus. But if you stay here, you will never become that man. He will _never_ exist because the things that shaped him, that made him will _never_ have happened.” Alec tells him, patiently, even though his heart aches with the words. The idea of Magnus, his Magnus just... ceasing to exist, it’s nightmarish and when he gets his Magnus back, he’s never letting him go.

“If I go back, will you be waiting?” Magni asks, his voice barely above a whisper, but Alec hears it anyway and nods.

“Yeah, I’ll be here.” He promises a little smile pulling at his lips. “True love cannot die, Magnus, and the love we have is true and eternal. When you get to this time, truly, honestly, the younger me will be there waiting. I promise you. How about we make that our deal? If you go back, I will be here waiting when you get here?” he asks, raising an eyebrow, as the warlock considers his words.

“True love cannot die.” Magni mumbles, breathing in deeply and letting it out on a sigh, before he nods at Alec. “I’ll go back, but do I have to go back now? Can I… can I stay for a little?”

“Only if you promise not to go back on your word later?” Alec asks, raising an eyebrow, Magni frowns at him, before shrugging.

“A warlock’s word is their bond.” Magni murmurs, and Alec snorts, having heard adult Magnus say that various times.

“Did Cat tell you that yesterday?”

“Mhmm. Warlock 101’s!” Magni answers, a giant grin on his face. “So, can I stay, for a little bit?”  

“Alright, how about a week? Seven is a magical number, should help with the wish magic to get you back, and you shouldn’t be here long enough for things to change too much.” Alec answers, praying he’s not making the biggest mistake of his life here.

“A week.” Magni replies, nodding his head.

“Since that’s sorted, do you want to meet my family? In person?” Alec queries, raising an eyebrow and grinning when golden eyes go wide. “Let’s go wake Ragnor, so he can portal us to New York.”

“What’s New York?”

“It’s where I was born, and where we met.” Alec answers, pushing away from the table and heading down the hallway, the pitter-patter of little feet following. “I can just tell this is going to be fun. Clary’s going to love you.”

“Biscuit?” Magni queries behind him and Alec nods.

“Biscuit. One day, you’ll tell me how you came to call her that.” Alec mutters under his breath and hears Magni laugh.

“I don’t know.”

“I meant older you, but the sentiment still applies, _he_ is still _you.”_ Alec says, before turning to pound on Ragnor’s door, Magni giggling beside him at the angry growling on the other side of the door. If they leave him, Ragnor might just sleep the entire day away. “Oh, angel, my mom is going to freak.” Alec exclaims, suddenly realizing that his mother might actually lose her damn mind at the sight of a child Magnus. He laughs and turns back to the door. “Ragnor, you get yourself up and dressed immediately or I’m going to break the door down. Little Magnus and I have things to get on with and we need a portal to New York!” Alec demands, only falling silent when a portal forms beside him and he pauses. “Huh, okay, thanks!” he yells, before turning to Magni and holding out his hand. “You ready for an adventure?”

“Ahuh!” Magni screams, rushing forward to put his hand in Alec’s and laughing as Alec pulls him through the portal into his future.

**Notes for the Chapter:**

> I can't remember why Clary's call Biscuit, if a reason was ever given, and I can't be bothered googling it, so...


	4. The Lucky One

**Notes for the Chapter:**

> Writing children is so hard. Remind me never to do that again? Thanks. 
> 
> My fancast for Kabniel is Katie McGrath... just because... Kabniel is the angel invoked to cure stupidity...

“Welcome to New York. The City That Never Sleeps.” Alec says, when they’ve stepped out of the portal, he smiles as he watches Magni’s eyes going wide, the kid pulling his hand from Alec’s and spinning in a slow circle, trying to take everything in at once, his mouth open in shock. They’ve arrived in the park outside the Institute, familiar ground for at least one of them.

“It’s so big and there are so many people!”

“There are currently at least seven billion people currently on the planet.” Alec says, laughing when the kid’s hand suddenly appears back in his own, being squeezed tightly. Alec hums and kneels down in front of Magni, waiting until the kid looks at him with wide eyes. “I’ll let you in on a secret, you saved all of them, every single one, and they don’t even know it.” Alec whispers to him, smiling when the little boy gasps. “A lot of little boys dream of saving the world, you actually get to.”

“Wow! I _really_ save the world? _Me_?” Magni queries, eyes so bright and full of innocence and hope that Alec almost chokes on the sight of it.

“Mhm. _You_.” He says, gently poking Magni in the chest. “You saved everyone when no one else could. It was amazing.” He assures him, standing up and ruffling his hair. “C’mon, let’s go find somewhere to sit down and I’ll call everyone to meet here.”

* * *

Lorenzo is the first to appear, he takes one look at Magni and almost has a heart attack. Alec would laugh if he didn’t understand what Magni’s presence means.

“You have to send him back!” Lorenzo exclaims, before glancing at the kid playing in the flowers across from them, and sighs, quietening his voice. “You have to send him back.”

“I know. It’s already been agreed. He’s staying for a week and then he’s going back to his own time.” Alec assures the warlock with a little grin. “I think he just wants to be a kid.” Lorenzo snorts at that and runs his hand through his hair.

“Yeah, well, he deserves to be one. How are you sending him back? How did he get here?”

“He wished upon the Pleiades, so he’s going to wish on them to go home, too.” Alec explains, looking up as the Shadowhunter contingent make their way across the park from the old church, immersed in an intense conversation about what Alec can’t quite make out yet.

“Oh, whatever Jace, you totally would have been a Hufflepuff!” Clary shouts as she gets within hearing distance. Alec startles a little when he suddenly finds Magni scrambling up into his lap and hiding his face against Alec’s chest.

“What?”

“You and Alec have this mutual loyalty society going on. It’s ridiculous, I mean, it’s not ridiculous because I’ve only had Izzy as my Parabatai for three weeks and if anything happened to her, I’d kill everyone and then myself, but…”

“Did you just quote Brooklyn 99 while talking about Harry Potter?” Izzy queries, but there’s a giant grin on her face.

“You know it!” Clary states before pausing and staring at Alec, her mouth falling open. “Excuse me, how could you not tell me your intention to make me an aunt?! I’m so upset!”

 _“What?_ ” Izzy yells, wheeling to look at Alec, and therefore, the child curled up in Alec’s lap. “Where’s Magnus? He promised to give me advance notice so I could pretend to be all shook and everything! Oh my gosh, he’s the cutest.”

“Well, if you guys would stop jumping to conclusions…” Alec says, cutting them all off with a look. Jace rolls his eyes while Simon huffs and stares at Magni with narrowed eyes. “Where’s mom?”

“She and Luke are off comparing the various beaches of the world or something. She asked if the world was ending, I said no, she asked if anyone was dying, I said I didn't think so, she hung up.” Izzy replies, shrugging her shoulders and causing Alec to laugh.

“Right, okay, well, she gets to miss out. Her loss.” He decides, before glancing down at the kid in his lap. “So, apparently young warlocks have ridiculously strong wish magic.” Alec starts to say, sees Simon’s eyes light up and the vampire lets out a little laugh. “Guys, I’d like you to meet Magnus, who has somehow wished himself forward in time and our Magnus back in time. He can’t understand a word any of you are saying, so you’ll need Clary’s rune unless you’re a language whizz.” He barely gets the words out before Clary is squealing with excitement, hastily scribbling the translation rune on her arm and kneeling down in front of Alec.

“Hi, Magnus! My name is Clary! I hope Alec’s told you good things about me.” Clary says, keeping her voice gentle until finally Magni peers out to look at her, Alec chuckling when Clary visibly refrains from squealing again. “He’s so cute.” Clary hisses at Alec before looking back at Magni again and waving.

“Biscuit.” The kid murmurs and Alec just rolls his eyes and huffs when Clary’s eyes light with so much joy, Alec's feels a smile pull at his lips. Clary has so very little to smile about these days.

“I let him see some of the videos on my phone.” He explains at the look Clary gives him; she narrows her eyes at his response.

“The good ones?”

“Uh, I kind of taught him how to use my phone and then let him just watch the videos he wanted?” Alec replies, shrugging his shoulders, Clary sighs.

“Ridiculous.”

“Move out of the way!” Izzy exclaims, suddenly shoving Clary aside and grinning at Magni. “Hi, Magnus, my name is Izzy. I’m Alec’s sister... and, therefore, _yours_.” Magni gives her a shy little wave and looks back at Alec with a look that Alec understands exactly as ‘save me’ because it’s the exact same look he’s seen on his husband’s face.

“Okay, let’s not overwhelm him! The two silent ones hanging back are Jace and Simon, and the ones over there chatting and pretending like they’re too good to be excited by this, are Andrew and Lorenzo. Lorenzo is our designated warlock minder for the day and he’s also the High Warlock around here, so if you’re going to use your magic, be sneaky, sneaky, about it okay?” Alec says, quickly breezing through the rest of the introductions.

“Are you allowed to tell him that?” Simon questions, laughing. “Then again, Magnus _has_ always been where you turn a blind eye, apparently.”

“ _Word!”_ Alec should be offended by the chorus of voices that agree, but he just shrugs his shoulders and doesn’t have anything to say against the truth.

“Alright, don’t go teaching the kid bad habits.” Alec grumbles, causing Clary to laugh.

“What? Like get into trouble and give you puppy dog eyes to get out of it?” she queries, raising an eyebrow, Alec snorts.

“Yeah. Exactly that.”

"It only ever works for him. The rest of us get a stern talking to and then punishment detail." she replies with a little huff. "It has to be the golden eyes, maybe it makes the puppy dog eyes more effective? I don't know..."

* * *

“Hello, Magnus.” He jumps at the voice that sounds suddenly from his side and he turns slowly to look, a small smile forming on his lips at his companion.

“Hello, Kabniel. What stupid thing did I do to get your attention?” Magnus questions, glancing at the bottle of seelie wine held tightly in his hand. “Aside from my drowning of my sorrows.”

“I always keep my eye on the warlock children, my siblings’ children especially.” Kabniel replies, tucking her hair behind her ears and reaching out to take the bottle from Magnus, inspecting it before throwing it over her shoulder, Magnus watches as it disappears. “You know me, so I assume I visit you in the future?”

“Once or twice.” Magnus replies, shrugging his shoulders. “I’ve done a lot of stupid things over the years, was around when the mundanes were doing their own stupid things… like the threat of Nuclear Winter, that was an experience.”

“That sounds bad.”

“So, the life particle. They decided to name it the ‘Atom’, you know 'cannot cut' and then went a step further and proved themselves wrong and split it, then figured out how to weaponize it enough that the whole planet could be destroyed.” Magnus replies, shrugging his shoulders. “You’ll see when you get there.”

“Sounds like fun, can't wait.” Kabniel tells him with an amused smile on her face. “It has been awhile since I’ve had to step in and keep the little darlings from totally destroying themselves, my siblings and I grow quite bored.”

“Is that why you didn’t stop my past self from making such a stupid wish?” Magnus questions, with a heavy sigh, then he pauses, turning to frown at her. "You could send me back."

“Free will is still a factor, Magnus. You should know this. Besides, wish magic is not my area of expertise.” Kabniel replies, her voice chiding, Magnus huffs and rolls his eyes. She was like that in the future, too. “Besides, when he comes back, he won’t remember any of it, when you go back, you’ll remember everything.”

“ _If_ he comes back.” Magnus mutters, pulling at his hair.

“He will.” Kabniel answers, with a little laugh. “He’s _you_. You’ve already lived what he is now living.”

“I wouldn’t have come back.”

“Not even if you gave your word?” Kabniel queries, waggling her eyebrows at him. Magnus huffs and rolls his eyes.

“Maybe.” He finally replies, considering it. “I don’t know.”

“Then, we’ll just have to see, won’t we? Now, you can’t spend your time here getting drunk.”

“Well, what else am I supposed to get up to? I’m a man out of time.” Magnus asks, lying back on the cold ground and staring up at the stars above him, where once they held so much hope for him, now they hold nothing but despair.

“Darling, I’ve watched you portalling around since you got here. Don’t pretend to be hopeless, it’s not a good look on you anymore.”

“ _Anymore?_ ”

“Well, when you were a child, it was kind of cute, and very endearing. Now, it’s just… mildly pathetic?” she answers, cocking her head to the side.

“ _Pathetic?”_ Magnus exclaims, more offended than he thinks he should be.

“Of course, you look like a kicked puppy dog. Find some way to kill the time that won’t end up killing _you._ I’ll be watching.” She promises, before vanishing from sight.

“Can’t you just say goodbye like a normal person?” he mutters to the thin air around him, but decides she has a point, and resolves to make something of his time here… in the morning, when he’s slept off the alcohol.

**Notes for the Chapter:**

> I really wanted Maryse to meet tiny Magnus, but I just wasn't feeling it :(


	5. So Long Sentiment

**Notes for the Chapter:**

> There MIGHT be little snippets sometime of what both Magnus's got up to during their week stuck out of time... but I got too impatient for adult Magnus to come back... 
> 
> Title is from So Long Sentiment by Celldweller, I was going to go with 'Time to Erase the Rest of Me' but figured y'all would freak out so... I went the safer option...
> 
> Okay, dang. I wanted a happy ending but... have a bittersweet one.

Alec’s not sure how the week seems to fly by and drag on all at the same time, but it does. The time with Magni is amazing and he enjoys getting to be responsible for something good in his husband’s life, even if he won’t remember it. But as the days go by, it gets harder for him to ignore _his_ Magnus’ absence. Rarely has he slept alone since their wedding and even then, he and Magnus spend so much time speaking either via fire messages or through their phones, that even when Magnus isn’t with him, he can still feel his presence, but this isn’t like that.

He’s relieved beyond words when the day finally arrives for Magni to go back, he’s sad, of course, but so relieved he’s almost sick with it. He doesn’t let the kid see that, though, instead, spends the day taking the kid sight seeing around Alicante, since they’d already gone around New York and various other cities around the world. The others join them for the visit, even Lorenzo, who reluctantly admits he owes Andrew a date and Andrew apparently decided to invite everyone else along, too.

When the sun begins to set, they retreat back to the loft, where Cat, Lorenzo, and Ragnor all argue over what to cheat up for dinner, resulting in a veritable feast. The feast is lovely, but it becomes a mess when Clary playfully throws a piece of cake at Simon and he retaliates, until they’re all diving around the loft for cover, lobbing bits and pieces of food at each other. Magni’s tucked up beside Alec behind the couch, a tray of cookies beside them, Alec just watches the kid giggling, popping up over the top of the couch to toss cookies wildly at the others, before diving back down, to giggle on the floor.

Alec watches him and feels his heartbreak for what has to be the thousandth time this week. How often will Magni get to just be a child when he goes back? How often will he be happy? But that’s something he’s not allowed to dwell on, not allowed to think about because, if he does, he’ll do something absolutely stupid and reckless and he _can’t._ So, instead, he watches, and feels his heart _break_ over and over again and promises that it just means he’ll love his Magnus twice as much when he gets him back, for the man he becomes and the boy he once was.

* * *

After they’ve all cleaned up the loft, which in actual fact means the warlocks have cleaned up the loft, Alec and Magni are left alone, an agreement Alec had from the others earlier in the week. So that when Magnus comes back, it can just be the two of them. With the others _finally_ disappearing through portals, Alec leads Magni up onto the roof, where Cat had disappeared sometime during the Feast Fight to set up a blanket fort, complete with a little sky window.

“Wow!” Magni exclaims, rushing forward to crawl into the little fort, looking up at the stars above him with a wide-eyed grin. Alec grumbles and groans as he kneels down to crawl into the fort, complaining as his knee pops. “You’re old!” Magni tells him with a laugh.

“Rude.” Alec mutters, though he feels a smile pulling at his lips. “I’m not old, I’ve just gotten myself hurt one time too many.” He argues, getting himself comfortable, looking up at the stars above.

“ _Old_.” Magni mumbles, then starts shrieking with laughter when Alec leans across to start tickling him.

“You’re cheeky.” Alec says, before he sighs heavily as he remembers how much trouble Magnus manages to get himself into. Not afraid to speak his mind, apparently, he’s never been afraid of that. He heaves a sigh and lies back against the cushions and blankets beneath him, Magni curling up against his side, the pair of them looking up at the stars.

“You’ll be here waiting?” Magni asks, Alec hears the fear in his voice for the first time since they’ve talked about Magni going back.

“I told you. True love cannot die.” Alec replies, wrapping his arm around Magni and holding him close. “You’ll find me, we always find each other and we always will, I promise.”

Alec wonders if memories of them will linger somewhere in the back of Magni’s mind as he grows up, memories that might influence him one way or another towards certain Shadowhunters. The _good_ ones. Why he above other Downworlders was always more willing to see the goodness that Shadowhunters could possess, why it was always such an intimate betrayal when those same Shadowhunters turned against him for one reason or another.

“I don’t want to go back.” Magni tells him, before soldiering on before Alec can speak, his eyes locked on the stars above. “But I must.” He murmurs, before beginning to mumble so quietly under his breath that Alec cannot understand him, his body glowing with magic.

“So, what happens now?” Alec asks, when the glow fades and Magni stops speaking, the kid grins and snuggles into Alec’s side, closing his eyes.

“We sleep.” Magni replies, his voice suddenly slurred with exhaustion. “Goodbye, Alexander.”

“Goodbye, Magnus.” Alec whispers, watching as the kid’s breathing evens out in sleep. "I'll miss you." he mumbles, before he licks his lip and looks up at the stars above him, thinking it won’t hurt if he makes his own wish, then he closes his eyes and eventually feels sleep claim him.

* * *

Magnus has just stepped out of a portal, back in his home village, when he suddenly feels off balance, his head aching, like it’s going to split open. He stumbles away from his portal before collapsing to his knees, wondering if this is it. If this is the moment he ceases to exist. He groans and clutches at his head, feels his blood rushing beneath his skin, reminding him so much of the failed magic transfusion from Lorenzo. His body trying to tear him up from within.

“I’m not ready to die.” He mumbles before his eyes roll back in his head and the darkness claims him.

* * *

Alec wakes to the sun shining in his face and he groans, bringing his arm up to cover his eyes, snuggling further into the blankets, but movement jostles the warm body pressed against his and he hears a familiar mumbling beside him and almost instantly he is awake. Sitting up quickly and turning to look at the person beside him, his chest heaving in his excitement.

“Magnus!” he yells, throwing himself forward, his arms wrapping tightly around his husband’s neck as he clings, sobs, and vows never to let go. “ _Magnus!_ ”

“I just had the weirdest dream.” Magnus mutters, slowly opening his eyes, only to hiss and close them again when he gets an eyeful of sun. “Maybe it wasn’t a dream.”

“If you went back in time, it wasn’t a dream.” Alec mutters, burying his face in Magnus’ neck, breathing in his husband’s familiar scent and relishing in his presence, tries to calm his pounding heart. Magnus is _back._

“The wish.” Magnus whispers, bringing his arms up to wrap around Alec, each of them clinging just as tightly to the other. “Oh Lucifer, he went back!” Magnus exclaims, breaking down into sobs. “I thought I was going to die!”

“Never.” Alec swears, shaking his head, clinging just that little bit tighter, and then just a little bit more. “I’d have found a way to get you back, even if he never went back.”

“I love you.”

“I love you, too. So much. More than anything.” Alec vows, feels his heart breaking all over again. “My love for you knows no bounds.” Magnus laughs and closes his eyes, breathing in Alec and slowly relaxing against him.

“He had a great time while he was here.” Magnus whispers, Alec snorts.

“ _You. You_ had a great time.” He replies, pulling back to look into Magnus’ eyes. “ _He_ was _you.”_

“Yeah.” Magnus admits, a funny little look in his eyes. “Yeah, he was. You’re pretty great with kids you know?”

“Oh, man, don’t even start. Clary and Izzy have been dropping hints all week…” Alec groans, shaking his head. “You know, I was pretty attached to the kid you were, so I don’t think we should be adopting anyone until I stop feeling like my kid’s suddenly gone missing.” Alec mutters, realizing for the first time that his words are true. He feels so, so _relieved_ to have Magnus back, _his_ Magnus, but he feels like there is something missing, something he will never, ever get back. It feels similar to when Magnus was trapped in Edom, but different, because Alec knew he’d get Magnus back. This just feels… desolate. He can’t have Magni, because Magni is _here,_ as _Magnus_. He can’t have both, can only ever have _one_.

“Oh, Alexander.” Magnus whispers, but he clearly doesn’t know what else to say as he falls silent, just holding Alec as tightly as he can.

“The heart is fucking stupid.” Alec grumbles, smiling a little when Magnus laughs against him. “I knew he was you and I knew I couldn’t keep him, but my stupid heart still had to get attached.”

“Yeah, that sounds about right.” Magnus answers with a sigh. “Come on, let’s go inside, I need to find some clothes, before we scandalize the neighbours, I can tell you all about what I got up to in the past and we can talk more about the fact that I… pretty much stole your child.” The warlock says, somehow managing to pull them both up onto their feet.

“You can’t steal yourself, Magnus.” Alec argues, but he lets himself be pulled back towards the loft, anyway, looking once more up at the sky, where he knows the stars remain but are invisible to the eye during the daylight hours.

_Goodbye, Magni. Good luck._

* * *

Eight hundred years in the past, give or take a few decades, a little boy wanders across his homeland, doing whatever it takes to survive. In the back of his mind a voice whispers that they’re waiting for him, somewhere and that true love can never die.

**Notes for the Chapter:**

> You didn't think Alec could take care of child Magnus for a week and then just send him home and there not be any consequences, did you? 
> 
> Also, just imagine Maryse hearing about this week later and being so pissed off she missed it.


End file.
